Light weight shell structures of high strength-weight ratio



Marh 1l, 1958 R. H. RoBlNsoN 2,826,521

LIGHT WEIGHT SHELL STRUCTURES OF HIGH STRENGTH-WEIGHT RATIO Filed March21, 1949 LIGHT WEIGHT SHELL STRUCTURES OF HIGH STRENGTH-WEIGHT RATIO RoyH. Robinson, Chicago, Ill.

Application March 21, 1949, Serial No. 82,592

S Claims. (Cl. 1S4-'-45.9)

This invention relates to improvements in strongly reinforced lightweight shells or sheathings for structural purposes and particularlywhere a minimum of Weight and high structural strength, disclosed in myco-pending applications, Serial No. 455,350, filed August 19, 1942, nowabandoned; Serial No. 492,914, led June 30, 1943, and issued as U. S.Patent No. 2,593,714; and Serial No. 545,630, filed July 19, 1944, andissued as U. S. Patent No. 2,626,804. It relates particularly tolaminated structures adhesively integrated under pressure and the novelcombination of relatively cheap materials such as wood veneers and/orresin treated paper, etc., with a skeletonized continuous metalreinforcement so Yas to provide great strength with light weight and atsmall cost. it provides thin shells which can be facilely andeconomically formed in mass production and uniquely installed for a widevariety of structural and ornamental uses.

Gne of the prime purposes of this invention a-mong others is to providea new and extensive use for commercially plentiful electrically fused orwelded metal fabric, long in common use for reinforcement in concretemasses, by novelly clothing same with impressed wood veneers and inharmonious relation with the general grain structure of the latter; toreinforce at strategic points the weaker fibers of the wood withembedded elongated tensile members and also filaments of high tensilestrength and superior physical properties, not possessed by the woodfibers; and furthermore to reinforce the metal fabric with strong sheetmaterial.

Similarly, a further purpose is to provide new fields for plywood panelsand sheathing by so giving new and greatly enhanced strength andphysical properties to this long employed and relatively cheap materialby so changing its structural character and strength-weight ratio andmaking it particularly desirable for a Wide field of usages where theseconsiderations are uppermost; and to provide a light weight wall-boardand sheathing material of exceptional tensile strength and ruggedness.

A further purpose is to provide strong structural sheets or films incombination with high tensile filaments and United States 4Patent O incombination with other wood, metal or other laminations after the mannerof applcants disclosures in his 2,826,521 Patented Mar. 11, 1958 ICCFigure la is a similar fragmentary sectional perspective view of thereinforced shell, the same as Figure 1 but with the inclusion ofsupporting structural sheets with filaments imposed on the central core.

Figure 2 is a fragmentary perspective view of such a structural sheetwith filaments, as employed in Figure la, and showing in somewhatdiagrammatic relation the metal reinforcement in position to be combinedwith same.

Figure 3 is a fragmentary sectional perspective view of anotherreinforced laminated shell with a modied form of metal fabric.

Figure 4 is a diagrammatic comparison and end view of reinforcementsimilar to that used in Figure 3 in relation to other and lessadvantageous cross sections of metal.

Figure 5 is a fragmentary sectional perspective View of anotherreinforced shell in which the reinforcement is exposed to view on itstwo faces.

Figure 6 is a fragmentary sectional perspective view of a reinforcedshell similar to that of Figure 5 but employing' a slightly differentVcross section of metal.

Figure 7 is a fragmentary sectional perspective view of a reinforcedshell with exposed metal members and a protected highly cellular core.

Figure 8 is a fragmentary sectional perspective view showing acombination of reinforcement and a covering of structural sheets withfilaments.

Figure 9 is an elevation showing a reinforced shell in place, as in abuilding structure, and method of installing same under tension.

Figure v10 is a fragmentary elevation showing a plurality of reinforcedshells in place, as for fencing, partitioning and the like, and methodof installing same under tension.

In Figures 1-la are shown adhesively laminated light weight shells S, oftypical balanced sandwich construction using an odd number oflaminations, as is preferred in preventing warpage. Outer wood veneers 1and 2 form the facings for the central core 3, the general axis of thegrain of the facings extending longitudinally and that of the wood core3, crosswise thereof, the grain directions being indicated somewhatdiagrammatically. The core member is of softer wood and facings ofharder wood,V although my invention is not limited to such arrangementor to such materials where other combinations are preferred for variousreasons. In order to develop extra strength through thickness (whichvaries as the square of the depth) the core member 3 is relatively thickin relation to the facings 1 and 2. At the same time in order tomaintain lightness of weight with this increased or greater thickness,la wood of low density, as for example balsa wood, is preferably usedfor the core. However, other light weight material, wood or syntheticcellular material or the like may be likewise so employed.

In order to give the plywood shell so formed with these l materialsexceptional strength, I introduce a strong tensile above notedco-pending application Ser. No. 455,350

of which this may be considered a continuing and divisional applicationwith regard to disclosures common to both applications.

Still another purpose of this invention is to provide improved and novelforms of electrically welded fabric and with particularly advantageousfeatures for combination with applicants fibrous and cellularlaminations.

The many other objects and advantages of my invention will 'be betterunderstood by reference to the following specifications when consideredin connection with the accompanying drawings illustrating certainembodiments thereof in which:

Figure 1 is a fragmentary sectional perspective view of a reinforcedlaminated shell.

reinforcement R between the core 3 and the faces 1 and 2. Thisreinforcement is in each case a single, molecularly continuous elementpresenting a rneshed but unwoven formation, the integral members ofwhich extending in one direction have at least the greater part of samein a different plane from those extending crosswise thereof, at leastthe greater part of which are in an adjacent plane. In Figs. l-la, thereinforcements R are formed with the cross members R1 moleeularlycontinu ous with the longitudinal members R2, both being formed of hightensile drawn wire made into a molecular unit by electric fusion. Suchmetal members producea tensile strength of some 70,000 lbs. p. s. i.with ordinary drawn steel. Where still greater strengths are wanted,

special steel alloys can be used, heat treated and tern pered and withstrengths two or more times the labove. Such fabricated reinforcementdrawn with ordinary steel, known originally as Clinton Wire Cloth andwelded Wire fabric has been produced commercially for the last 40 or 50years and has been in common use these many years for reinforcingconcrete in which it is cast. Notwithstanding that fact, the use of suchmetal units, uniquely impressed into assemblages of wood veneers inaccordance with this applicants disclosure has been unknown to the artand never been hit upon in this extensive arts history as evidenced bythe patent records.

In applicants novel construction, this ordinary commercial weldedwirefabric'which is made with round wires may be employed for theseelements R. However, I' prefer in vthe prefabricating 'of these hightensile units to employ specially drawn wires of shapes I have devisedfor better serving the several and peculiar functions of my newcombination. Thus in Figs. l-la, instead of the Vstandard round wire forthe members R1, the wire is drawn to something of a triangular shapewith the outer point to present a suitably rounded bearing -surface forimpressing in the soft core 3. The width of this rounded bearing surfacewill best be determined by the nature and hardness of the core in whichit is to be introduced under pressure by which the laminated shell isformed. With a harder core wood I correspondingly narrow or make morepointed this outer penetrating and bearing surface. To further grip thecore and mechanically interbond these members R1 with same, I alsopreferably undercut the lower and under sides of same, as at 1a, so thatin the process of impression the compressed wood expands back underthese undercut portions to provide this mechanical interlocking. Withthe thinner and harder veneer facings 1 and 2, the metal members R2 arecorrespondingly smaller and drawn to a penetrating triangular point atthe outer edge While the under or base edges are likewise undercut vat2a for the mechanical bond. The form and relationship of these membersR1 and RZ are shown in larger scale in Fig.- 2 for greater clarity.Therein it will be seen how the members are electrically fused togetherwhich occurs at all crossing points in the various forms of thereinforcements R. Normally, as indicated in Fig. 2 the crossing memberswill slightly countersink with regard to each other and small metalshoulders will form as indicated in the fusion F, the whole structurebecoming in the process a molecular unit of great strength throughout.In connection with assemblage of the various laminations forV theproposed shell, I preferably dip, spray or otherwise combine thereinforcements R with suitable adhesive material so that the bond withthe Wood or other surrounding material is adhesively improved inaddition to mechanical bonding. While my undercuttings as 1a and 2a canbe omitted in drawings of these tensile members I prefer to include themwhile at the same time keeping a broad contact and fusion basefor themolecular union of the crossing members which my special shapes provideasin distinct contrast to the tangent crossings of round wires, while atthe same time requiring a lesser amount of metal even though overalldimensions of height and breadth are kept the same as that of a roundcross-section, and so as to offer strong resistance to bendlng momentsin either direction and either in the fabric by itself or in thereinforced shells S. A particular feature of the invention is toproportion, as noted, the crosssections of the members as R1 and R2 indirect relation to the materials with which each respectively is to becombined in pressure penetration, both in Vconsideration of sofacilitating the pressure impressing and still more to secure thereaftera bearing base for the reinforcement proportioned to the softness orhardness of the wood or similar bearing material. Thus in Figs. l-lawhere a large soft core of balsa wood or the like is provided, the largecross-section of the members R1 secures a large bearing base for themetal member under stressing.

Furthermore the large size of the members R1 causes so much greatercompression of the fibres of the wood surrounding these membersfollowing impression with a so-increased density of the supporting corewood at these points, as indicated in the drawings. By this means,

and by further centering the opposite members R1 im pressed in theopposed faces of the core member 3 in vertical alignment, as shown inFigs. l-la, a column of harder denser compressed wood or material isbuilt up between and about the opposed members R1 so as to form, withinthe core, an I-beam construction on spaced apart centers and inconjunction with the metal members R1 forming a part of same. Also, itwill be noted with a sufiiciently harder material, this large size ofmetal cross-section would not be feasible for facile mpression so thatin my novel combination the sizes and shapes `of my reinforcementmembers are not only determined by the nature of the respectivelamination with which each is to combine in the structural shell formed,for considerations of strength, but, furthermore, for considerations offacile pressure forming and integrating of the shell.

As will be noted in Fig. la, when desired, I augment the aforesaidbearing surface of the soft core 3 for the reinforcement members R1 byfurther including bearing sheets or structural lilms P, positioned onthe surfaces of the core 3 in the preliminary assemblage of the severallaminations of the contemplated shell and so that these bearing sheets Pintervene between the members of the reinforcement R and the core 3 andso support the reinforcement in the stressing of the finished shell byacting as a saddle for same to sit in and so distribute bearing stressesacross and all over the soft core instead of permitting otherwiseconcentration of same directly under the members R1. The nature of thesestructural and reinforcing sheets P, which are further disclosed in myabove noted co-pending applications, is better shown in Fig. 2 wherein asheet or film 4 has combined with it suitable adhesive material,preferably a thermo-setting plastic, such as phenol-formaldehyde.Impregnated structural paper of the papreg type which is capable ofdeveloping remarkable physical properties with tensile strengths of35,00040,000 lbs. p. s. i. when given nal cure under heat and pressureis a preferable base film or sheet and in any desired number of ply. Onthis I have applied in manufacture and while the impregnating and/orcoating resin is in a sticky state substantially parallel rows of strongtensile filaments, as 5 and 6, which are so made to adhere to thesurfaces of the paper in the preliminary setting of the resin adhesive.While a variety of strong fibers or strands, organic, inorganic orsynthetic may be used for these filaments, I preferably employ glassfilaments where the greatest strength and other high physical anddesirable properties are of prime importance. As these are in themselvesnonporous and so, l nd, are harder to bond adhesively to otherlaminations when presenting a solidly covered glass fiber front orsurface, I preferably space these iilaments slightly apart in stickingthem on the sheet, film or papreg so that each filament by itself isfree to impress itself into the wood grain or other material of thelamination with which the structural sheet element P is combined underpressure, as in Fig. la. Also, to so best impress with and into the woodgrain of crossing wood veneers, as 1 and 3, or 2 and 3, in Fig. la, Iapply the filaments on one surface, as 5, in one direction and lilamentson the opposite or underside in crosswise direction so that both willapproximately conform to the grain axis of the veneers into which eachis to be impressed in the assembled laminated shell as in Fig. la. Thesedirectional arrangements of the so applied filaments may be greatlyvaried to suit the arrangement of the veneers of the intended shell andbe crosswise of each other at any angle as well as right angles asshown, so as to suit wood layers .S9 arranged; or they may be laid inthe same direction on both of the sheet 4 surfaces, or again they may beapplied to only one of the surfaces. Alsofa ply of many such sheets andwith filaments on each ply in any of such arrangements may be built uppreliminarily and for such use as P in Fig. 1a.

To further make it possible to combine these sheets P with thereinforcement R, as .Rl-R2, and press same together as shown in Fig. laand without thereby fracturing or overstraining` these sheets byotherwise stretching them to conform tothe extended contour created bythe presence of the metal members (as compared with the area of a fiatsheet laid upon same for the pressure integrating), i provide creasedribs or folds 7 in the prepared sheets l, spaced apart to match thespaced centers of the metal-members, as Rl. The size of these ribs 7 iscalculated in relation to the size of the members as Rl with which thesheets are to be used and of such dimension that the sheet P is drawnproperly and to the desired tightness when the reinforcement R isimpressed upon it. By this means, also, a slight and desired tension canbe given the sheet as it is so impressed so as to remove any desiredremaining stretch and give same the highest tension reaction in theintegrated and hardened shell, and this without over-stretching thesheet. Instead of a single rib or fold allowed for each member as R1, aplurality of smaller ribs or folds or indentations may be provided whichwilll equal the same increased area for the required expansion. It alsois not necessary that in assemblage exact register be had between theribs as 7 and the members R1 as in the pressure joining the excess sheetmaterial, so provided, will be drawn out in any case and to the contourof the so indented core 3. In cases where the wire or metal members of Rare so` small that undue stretch will not be brought to bear on thesheets P in the above noted pressure assemblage and integrating, theseribs or folds can be omitted.

In preliminary assemblage for the forming of the shells S, it will beunderstood that the several elements forming the laminations are looselyimposed one on the other in the proper order in the press which may beof the hydraulic or other mechanical type or one operating with uid bagpressure or a combination of both. The contacting surfaces of theveneers are coated or otherwise associated with suitable adhesive, as isalso preferably provided on the reinforcement as well. When thecomponent elements are all in` proper position, the pressure, and heatwhen required for the adhesive employed, are applied for the properperiod and the reinforcement R thereby forced into the grain of the woodveneers or layers, the wood so compressed about the reinforcement andthe whole laminated shell so integrated with the final curing orhardening of the adhesive. Single sectional or continuous shells can beso formed in a matter of minutes in mass press'production. It will alsobe understood that in the gluing or adhesive bonding of the laminationsthe structural sheets P, when used, also` provide in` themselves anadhesive bonding agent similar to impregnated tissue known in the tradeas Tego and made for bonding veneers together, Where the` high,`structural` strength of the papreg materialis not required, my filaments5 and 6` can be similarly embodied in such tissue bonding material asTego in Vits manufacture so that my laments may be impressed into thegrain of the wood to supply the necessary reinforcing strength while theimpregnated or otherwise adhesively treated tissue or film supplies thegluing agent for the contacting laminations. n the figures the joint orcontactinglines of the several component laminations and the metal tonon-metallic material may be considered asl glue lines or surfacesadhesively treated for bonding. It should also be noted that asindicated or shown in Eigs. 14n and others, the` members of the metalreinforcement R can extend*` outward of the edges-of the shells forproviding ready metallic means for facile connection of shells to eachother or to framing or other anchorages, preferably by welding of metalto metal. When not so wanted they may be out off or the shellsmanufactured with iiush edges in whole or part. Both arrangements areshown among the several figures.

In Fig. 3 is shown a modied form of applicants 3 ply shell wherein thereinforcement R is similar to that of Figs. l-la with mesh formingmolecularly continuous members R3 and R4 drawn to a unique shape havinga barbed like and undercut head designed to readily penetrate the woodlaminations .and` embed in same when the loose assemblage is subjectedto pressure integrating as already described. The outer veneer facings 9and 10 are thereby adhesively bonded to the core wood 8 as well as beingmechanically bonded throughout by undercut anchoring A of thereinforcement members R3 and R4. The R3 members are of larger crosssection for embedding in the thicker softer core wood S while the R4members are proportioned to a smaller cross section as determined by thehardness and/ or thickness of the facing veneers 9 and 1). In thisinstance the members R3 of one layer of ythe reinforcement element arein staggered instead of directly opposing relation to the correspondingmembers of the other layer of reinforcement impressed in the other faceof the core 3 and all reinforcement members embed, as always, indirectional harmony with the general grain axis of the engagedlamination.

The special cross sectional shape of these special reinforcing membersas R3 are more clearly illustrated in the larger scale Figure land insomewhat diagrammatic comparison with other shapes of relatively lessefficiency for the intended purposes. While ordinary welded fabricformed of round wires may be used' in applicants shells, as alreadynoted, the round wires as indicated in dotted cross sectional shape Wpresent many disadvantages. Among these it will be readily observed fromthe figure that the blunt round face of Wis not adapted to penetratingthe wood as compared with the barred head of applicants member R3 andwhile the latter has the same over-all dimensions of height and breadthfor stiffening resistance to bending moments applied in either directionas compared with W, a much smaller quantity of metal and weight isemployed in R3. Likewise while R3 has the same width to sustain itselfin pressure on the Wood lamination, (as 3 of Fig. 3), this is located atthe base where it does not interfere with the impression of the memberin the wood as does the same width of metal in W which is spaced awayfrom the base or at the center axis of the circle. Furthermore R3 gripsthe wood relatively deep therein with its undercut A whereas the onlygrip for mechanical bond which W presents is on the underside of thecircle and so at the more nearly surface portion of the wood, withcorresponding weakness. Again where W presents only a tangent surfacefor fusion welding with cross members, R3 (and R4) each present theirbroadest width atV the base for a broad fusion and bearing surface andto stify resist bending stresses. To further resist these and provide aswell a large section of metal for fusion` applicant prefer-ably providesthese members as R3 and R4V with a` thickened base B, as shown. Infusion, `producing the metal molecularly continuous element, the opposedmembers as R3 and R4, the same as R1 and R2 of Figs. 1la and 2, willhave their contacting bases slightly countersunk with regard to eachother in the normal union and so making `a particularly strong crosssection a-t such points but where this is not preferred thecountersinking can be avoided by lighter or spot-welded union. As afurther alternate, where the bond of the undercut A is not required, mywire shapes` may be drawn with the undercuts omitted and the sidesthose` of a simple triangle as indicated bythe dotted `lines W1. Alsowhen stessi 7 desired the sharper point of the shapes as R3 and R4 maybe blunted to any desired terminal curvature as C1 for example. Myspecial fabric employing any of these shapes is not only particularlyadapted to my shell structures but also, it will be readily seen, hasdistinct advantages of strength and stiffness and with a reduced amountof metal as compared with the common commercial welded fabric and veryparticularly for fencing as well as reinforcement,

In Figure 5, I combine my reinforcement R, using t-he barbed members R5and R6 similar to Figs. 3 and 4, with thinner veneers to make a two plystructural shell S in which'the metal members are so exposed to view onboth surfaces with veneer strips exposed between same 'and adhesivelyand mechanically bonded while held bythe undercuts A under which theveneers 11 and l2 are forced, compressed and held. By being socornpressed, subsequent shrinkage of the wood veneers, if `occurringwill not present an open and unsightly joint. At the same time by usinghandsome metal, as chrome or stainless steel, or even copper, oraluminum alloys, etc., and combined with choice and beautiful veneerwoods, new and unusual architectural effects may be had forpartitioning, sheathing and a great variety of ornamental as well asstructural purposes. The veneers 11 and 12 cut to individual widthsslightly wider than their occupied spans may be forced between the metalmembers in the pressing assemblage and as such separate veneer units.However, advantage may instead be taken of the special cutting points Cprovided by the members R5 and R6 so that whole veneer sheets formed inwidths to cover the span or broad sections of the whole shell may belayed up with 'the reinforcement R in the preliminary assemblage and theveneer then forced onto the cutting points C of the members R5 and R6,by press or rollers, so as to crease and cut same and force the so cutveneer strips down between the reinforcement and under the undercuts A,the veneer sheets being of course first treated or coated with adhesiveso as to form a completely and adhesively bonded shell under thepressure treatment so applied. It will be noted, of course, that thecutting points C, crease and cut the veneer along the grain axis with acorresponding minimum of resistance, and it will be further understoodthat the cutting angle of C is made, in the fabrication of the metal, tobest suit its intended purpose.

In Figure 6 is shown a similar shell to that of Fig. 5 with theexception that in connection with the reinforcement R, its metal membersR7 and R8 are drawn to a simpler cross section with undercut sides forlocking the veneers 13 and 14, as shown, and forming a quintagonal crosssection with the creasing and cutting edge C and with a broad bearingand fusion base but not as large in proportion as that of R5 and R6 ofFig. 5.

Figure 7 shows a modified shell where the central core lamination 15 ispreferably a light cellular sound deadening and insulating member usedin place of the balsa or soft core of Figs. l-ltz. While a variety ofmaterials may be used for this cellular filler or core member, cellularcellulose acetate, known as Strux and weighing only 6-7 lbs. per cubicfoot while having exceptional strength for its low weight, isparticularly suitable for this lamination. In the structure of Fig. 7,this highly cellular core is not used to embed and support directly themetal reinforcement R. Instead, as shown, the members thereof, R9 andR10, combine directly with the veneers 16 and 17, on the one side, andsimilarly 18 and 19 on the other side of the shell S, these veneersbeing denser and forming a strong bearing plate for supporting thereinforcement R and covering the softer core 15. Where furthersupporting strength is desired, my reinforcing and sustaining bondingand structural sheets P, with or without my filaments 5 and 6, areinterposed between the veneer plates and the faces of the core 1S,the-so multiple laminated shell assemblage be- 8 ing adhesivelyintegrated throughout in connection with theA pressure forming of same,as in the case of all my other structural shells S. In Fig. 7, it willbe noted, I show another special shape for the reinforcement members R9in fused molecular union with members R10, in this case of simpletriangular section although other forms are optional. However, themembers R9 are made to present flat flush metal surfaces Ibetween thestrips of veneers 16--16 and likewise 1S-18 which are mechanicallylocked in by the undercut cross section of the metal with its outerflanged-like lips R9F as well as being adhesively joined to the metal.These veneer strips 16, and correspondingly 18 are forced between themetal members R9 under compression, as from a preliminary archedposition between same and when the shell is completed, a very fineornamental effect may be had with many selections of handsome woods tointerpose between polished metal surfaces provided by the members R9.The latter' are in fused molecular union with the cross members R10which are impressed in cross veneers 17' and 1S respectively after themanner already described in the preceding figures. It should beespecially noted that when desired in combining architectural andstructural effects, and further to 4reduce costs, I make the members R10of different metal from R9. Thus the exposed members R9 may be ofexpensive chrome steel and the members R10 of ordinary cheaper steel.Similarly ornamental but weaker copper may be used for the R9 portionsin fused union with stronger steel forming the R10 portions. A greatvariety of combinations may so be made in a thus entirely new and highlyuseful form of welded fabric unknown to the present art. This may applylikewise to the reinforcement R of Figs. 5 and 6 where the two oppositeand exposed sides of the shell or panel can be made to present differenteffects and when joined in an extended shell or partition can so presentalternating architectural effects. Similarly in shells as in Figs. lla,and 3, where the reinforcement R is concealed as Iregards both mem-bers,greater strength when desired can be introduced into one set of membersor lower cost of metal in another `set of members by using higherstrength and more costly steel alloy in one set of members and lowercost weaker steel in the cross members molecularly joined therein as thesituation may recommend. In addition to applicants shells S being madewith metal members projecting from one ormore or all edges as desired aswell as finished flush, as already noted, these shells may be formedwith mechanically in terlocking edges, as tongue and grooved, and Fig. 7shows such an arrangement whereby extended assemblages of finishedshells may be set up in such interlocked and closed relation with thematching tongue and grooves adhesively joined while being forcedtogether. It will be understood that in Fig. 7 the bearing plates formedby the sheets P or and the harder veneers 17-16 or 19--13 serve todistribute over the entire surface and body of the softer cellular core15 the otherwise more locally applied stresses arising from thestressing of the sustaining metal skeletons provided by thereinforcements R. It should also be understood that a highly cellularmaterial of synthetic or other creation may also be used for the coremembers of the shells S of Figs. 1-1a, 3 and the like, in lieu of woodsor other fibrous material of any degree of softness as may be selected,as in the case of Fig. 7 and vice versa, woods and Aother fibrous orcellular material may be used for the core 15 of Figure 7. Figure 8shows a structural shell where my special structural sheets P, eithersingly, or in multiple groups, are applied on both sides of myreinforcement R and adhesively integrated under pressure and with orwithout other additional covering laminations of veneers or othersuitable materials (not shown) employed as in Fig. la. When these sheets4 and likewise the imposed laments, when included, so formed about themolecularly continuous meshed but unwoven metal, are polymerized inadhesive union with each other and the metal, a remarkable structure initself is produced forming as it does thin walls of metal-like strengthwith cellular parallel-rows of ridges in one plane crossing andcommunicating with similar rows in a contiguous plane and with the socontinuous connecting rows of elongated cells at the same time filledwith molecularly continuous metal extending throughout all of the cellstructure so formed. With a minimum of weight, it will be at once seenthis multiple arch construction of the skin, crosswise in two planes asit is and containing, within, a complete and continuous metal fillingskeleton, provides a unique structure of great strength and suitable fora wide field of structural uses. Applicants imposed filaments, which canbe arranged in a number of different directions to meet correspondingstresses, not only greatly increase the tensile and compression strengthbut also notably enhance the flexural and shock absorbing values of theshell and can further be arranged to provide directly against shear whenwanted, this by including sheets with the filaments disposed at 45degrees with the reinforcement mesh and in opposite directions, at suchangle, on the opposite sides ofthe sheet or sheets d (not shown). Thissame applies to other of applicants shells, as for example Fig. 7 wherethe filaments on the core (1S) side can be arranged to resist shear withone set extending at a righthand 45 degrees and the other set extendingat a left-hand 45 degrees. While any number of ply of 4 or P may beemployed at will and with any combination and numbers of directions ofthe filaments embodied in P, two 2 ply, one on top and one underneaththe reinforcement R, are shown in Fig. 8. The top two sheets 4 havetheir filaments 5 and 6 so oriented that both surfaces of the outersheet and the upper surface of the under sheet have these in paralleldirection with the members R11 of the reinforcement, while the undersurface of the under sheet has the filaments crosswise thereof and s0parallel with the direction of the reinforcement members RU.. The twobottom sheets 4 have their filaments arranged directionally so thatthose of the outer exposed surface of the bottom sheet extend parallelwith R11 while the remaining three surfaces of the two sheets have the`filaments thereon extending parallel with the members R12.. This alsoso provides for the contacting filaments 6, of the opposed surfaces inthe middle of the laminated shell S, to come together parallel of andinterbond in somewhat of a tongue and groove formation when the looseassemblage of sheets P and reinforcement R are finally forced togetherunder pressure and adhesively integrated in such position therewith. Asnoted, the further inclusion of sheets with 45 degree filaments willfurther fortify the shell against shear and some or all sheets may havefilaments on only one surface or none as may be predetermined in theshell design. The greater strength of uni-directional filament or anapproximate approach to same, as compared with conventionally wovenmaterial has been brought out in applicants aforesaid co-pendingapplications and is fully recognized as result of laboratory tests inthe field of plastics. Applicants sheets P take full advantage of thisimportant fact. They make it possible to handle and apply unwovenuni-directional filaments in Wholely unwoven form where in the field ofassemblage it would be impossible or impractical to handle and employthe separate loose unwoven bers or filaments. They also make it possibleto cut these sheets with their filaments to any desired shape and sizeand hold the materials in position. without trouble whereas, as in glassor fiberglass cloth, the loose weaving frays and unravels and cannot beheld to sharp edges or position. The unwoven filaments would of coursepresent an even more impossible situation in such matters. It is alsopossible to obtain a close interbond between filaments meetingparallelly and in unwoven form where opposing sheet surfaces are bondedtogether, as shown in Fig. 8, whereas the same does not occur withopposed woven filaments. Still another advantage of my structural sheetsP with their filaments is that when wanted they can be polymerized ornally cured before use in laminated shells. This is important in as muchas in many cases the 'heat and pressure that may be required for thisfinal cure of these structural sheets is not available or employed inshops where laminated work is `built up and glued with cold gluingprocesses and where notwithstanding these cured structural sheets ofmine may still be included in gluing up the intended shells. Furthermoreadvantage is often gained and desired by having the filaments, as glassfor example, pre-tensioned in the forming of a -shell and to the properdegree, to remove stretch and increase resistance to tensile stressing.To further provide such advantage, my structural sheets can be made withthe filaments readily so tensioned in the manufacturing process andwhere it would not be feasible or possible in the assemblage and `gluingof laminated shells and under various conditions. Again, 'it should benoted that while I do not limit my structural sheets to any one film orsheet material or filament material or adhesive employed, my combinationof impregnated paper as papreg with approximate strength approaching40,000 lbs. p. s. i., with adhesively coated glass filaments developingstrengths (tensile) between 100,000 to 200,000 lbs. p. s. i. or more,make shells possible of tremendous strength, of very light weight andcorrespondingly high strengthweight ratio.

ln Figures 9 and 10 are shown somewhat diagrammatically the manner inwhich my various structural shells as above described can be combined,installed or erected to great advantage so as to take advantage of theirembedded molecularly continuous metal skeletons forming thereinforcements R by drawing the latter into tension and then securingsame by welding or other means to supporting metal frames or anchorageswhile the thin panels are thus taut. In Figure 9 is shown a shell S usedas a partition between a Hoor 20 and a ceiling 2l. This shell panel mayhave its reinforcement R concealed from view as in Figs. l-la, 3, 7 and8 or may show exposed metal strips on the surfaces af'ter the manner ofFigs. 5, 6 and 7. In the present instance the vertical metal members ofR have their surfaces so exposed and the horizontal or longitudinalmembers concealed as indicated. The latter have both their endsprojecting from the shell, however, for tensioning and anchoragepurposes, after the manner `of R6 in Fig. 5 and these when erecting thepanel are welded at one end to a metal upright as a steel channel orangle iron 22 which is securely erected in place. The reinforcement R isthen temporarily secured at the other end of the panel to a gripping andtensioning device indicated in dotted line for example by a bridle oryoke Y which is made to draw the reinforcement R to the desired tensionin the direction of the arrow T. While the panel and reenfor-cement areso tensioned, the vertical members of the reinforcement which also havetheir ends corresponding to those of R5 of Fig. 5 likewise properlyprojecting from both edges of the panel are welded or permanentlyanchored to steel channels, angle irons or the like7 2.3 and 24- (whichare permanently attached to the door Ztl and the ceiling 2l,respectively) at their respective ends, the various weldings beingmarked F. Likewise the other ends of the longitudinal members of R, heldin tension are welded or otherwise secured to another erected metalupright 25, corresponding to 22 both of which serve as studs. The panelS, thus secured in tensioned position on all four edges, the tighteningdevice Y is slackened and removed and the operation can be continuedagain with another panel being welded to 25 and the procedure repeated.In this way partitioning, wall structures and the like of greatstrength, although very thin, can `be provided and with only a fewsupporting studs as compared with conventional practices. At the sametime highly attractive and modernistic architectural eilects can be had.In this connection, Aby forming the shells S in square sections anderecting same as in Fig. 9 with alternate panels set vertically and theintermediate panels horizontally with respect to the exposed metal ribsor/ and wood grain axes, and also with dilerent colored metal or/ andwood veneers in alternate panels. Other arrangements include alternatepanels with concealed metal reinforcement as in Figs. l-la, 3, etc.,between panels with exposed metal ribs as in Figs. 5, 6, 7 and 9. Theseare only `some of the combinations and architectural effects which myshells make possible.

In Figure 10 is similarly shown how a series of separate shells S may bejoined to each other and to an occasional post or upright as forfencing, partioning or other structural purposes. In this instanceshells of the type of Figs. l-lrz, 3 and 8 are shown and with only thelongitudinal members of the reinforcement R extending and welded oranchored to holding connections. Thus the members R1 arrangedlongitudinally for the several shells as S1, SZ and S3 and haveprojecting ends, have their ends Welded to connection ribs or othermetal plates Z6 and 27 so these panels are joined with one continuousmetal reinforcement which in turn has the projecting ends of the membersR1 in turn welded to a metal post or upright 28. Thereafter thecontinuous shell S1S3 is tensioned with suitable device, represented bythe yoke Y, and in the direction T, to the proper degree and the otherprojecting ends of the members R1 welded to the metal post or upright29, the weldings throughout being indicated as F and the upghts beingsecured in the base or ground 30. The tensioning yoke is then releasedand the operation continued with additional sections of shells. It willbe seen that with this tensioned installation and the great strength andlight weight of the shells, long lengths of the fencing, etc., may beerected with but a small number of posts or studs while the anchoredtensioned resistance will hold against strong impacts and pressure.Shells and assemblages such as these can be used for light strongrooting and the like and tensioned across the entire spans or coveringsand on arched structures extending and tensioned from ground to ground,as in airdromes and the like.

It will be understoodthat I do not limit my invention to any particularuse and that I am aware that the details of construction and method ofprocedure may be con-V siderably varied wihout departing from theprinciples and spirit of my invention and I reserve the right to makeall such variations as fall within the scope of the following claims.

I claim as my invention:

1. A laminated structural shell adhesively bonded together and includingone lamination of wood with rows of spaced apart depressions impressedtherein and extending at least approximately in the general direction ofthe grain of same bonded adhesively to another wood lamination alsohaving rows of spaced apart depressions therein and which extend atleast approximately in the general direction of its grain and crosswiseof and communicating with said depressions impressed in the firstmentioned Wood lamination and a. molecularly continuous metal fillingoccupying and common to rows of depressions in both laminations andforming a unitary meshed framework in unwoven formation with the meshmembers extending in one direction superimposed on the mesh membersdisposed crosswise of same.

2. A laminated structural shell forming a sandwich construction havingin combination two spaced apart reinforced shells of the kind describedin claim 1 adhesively bonded to an intervening core member forming asofter more compressible lamination and of lower specific gravity.

3. A laminated structure as recited in claim 1 in which one of saidopposed woodlaminations is harder than the other and the mesh memberswhich are impressed substantially in the general direction of and in thegrain of the harder lamination are smaller in cross-section than themesh members disposed crosswise of same and impressed substantially inthe general direction of and in the grain of the opposed softerlamination.

4. A laminated structure as recited in claim 1 in which one of saidopposed wood laminations is harder than the -other and the mesh memberswhich are impressed substantially in the general direction of and in thegrain of the harder lamination are so shaped and have such crosssectionas to more facilely impress in wood as compared with the shape andcross-section of the mesh members disposed crosswise of same.

5. A laminated structural shell as recited in claim 1 with at least themesh members extending in one direction held in tension.

References Cited in the file of this patent UNITED STATES PATENTS246,853 Woods Sept. 6, 1881 488,809 Heepe Dec. 27, 1892 1,215,570 MixFeb. 13, 1917 2,004,553 Een June 11, 1935 2,261,264 Luty' Nov. 4, 19412,285,031 Hickman June 2, 1942 2,312,227 Yant Feb. 23, 1943 2,428,325Collins Sept. 30, 1947 FOREIGN PATENTS 575,798 Germany May 5, 193363,155 Denmark Feb. 5, 1945 609,150 Great BritainY Sept. 27, 1948

1.A LAMINATED STRUCTURAL SHELL ADHESIVELY BONDED TOGETHER AND INCLUDINGONE LAMINATION OF WOOD WITH ROWS OF SPACED APART DEPRESSIONS IMPRESSEDTHEREIN AND EXTENDING AT LEAST APPROXIMATELY IN THE GENERAL DIRECTION OFTHE GRAIN OF SAME BONDED ADHESIVELY TO ANOTHER WOOD LAMINATION ALSOHAVING ROWS OF SPACED APART DEPRESSIONS THEREIN AND WHICH EXTEND ATLEAST APPROXIMATELY IN THE GENERAL DIRECTION OF ITS GRAIN AND CROSSWISEOF AND COMMUNICATING WITH SAID DEPRESSIONS IMPRESSED IN THE FIRSTMENTIONED WOOD LAMINATION AND A MOLECULARLY CONTINOUS METAL FILINGOCCUPYING AND COMMON TO ROWS OF DEPRESSIONS IN BOTH LAMINATIONS ANDFORMING A UNITARY MESHED FRAMEWORK IN UNWOVEN FORMATION WITH THE MESHMEMBERS EXTENDING IN ONE DIRECTION SUPPERIMPOSED ON THE MESH MEMBERSDISPOSED CROSSWISE OF SAME.